[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: XML aggregation question?

• From: Philippe Poulard <Philippe.Poulard@xxxxxxxxxxxxxxx>
• To: Michael Kay <mike@xxxxxxxxxxxx>
• Date: Mon, 28 Aug 2006 14:53:51 +0200

Michael Kay wrote:
>>Based on all the comments thus far as well as reading some of 
>>the articles/documentation on eXist, it would seem that an 
>>XML database is really the only viable choice if I want to 
>>keep my data as XML and still provide aggregated views across 
>>the instances based on values of attributes (or other 
>>expressions using XPath and/or XQuery).
> 
> 
> 
> This isn't absolutely true. For example, the W3C XSLT test suite (not
> published, unfortunately) is a collection of over 5000 XML documents held in
> filestore, and it's quite feasible to run queries in Saxon (using either
> XSLT or XQuery) across this collection. For example, to count how many of
> the stylesheets in the collection specify version="1.0" on the
> xsl:stylesheet element, use:
> 
> count(collection('file:///c:/xslts_1_0_0/TestInputs?select=*.xsl;recurse=yes
> ')
>          [(xsl:stylesheet|xsl:transform)/@version='1.0'])
> 
> What you don't get with this approach is performance. There's no database
> load operation, so there are no collection-level indexes: the system works
> its way through the directory parsing and testing each individual document.
> But it's still very useful (and surprisingly fast) for the occasional ad-hoc
> search.
> 
> Michael Kay
> http://www.saxonica.com/
> 

hi,

Just a comment about the syntax :

-Saxon's syntax :
collection('file:///c:/xslts_1_0_0/TestInputs?select=*.xsl;recurse=yes')
-Ant's syntax :
<fileset dir="file:///c:/xslts_1_0_0/TestInputs" includes="**/*.xsl"/>
-Why not using definitively the XPath syntax ?
file('file:///c:/xslts_1_0_0/TestInputs')//*[ends-with(name(.),'xsl')])
or
file('file:///c:/xslts_1_0_0/TestInputs')//*[@extension='xsl']
or whatever à la XPath ?

The XPath syntax was adopted in Active Tags for many purposes : file 
systems, HTTP requests and responses, web cookies, etc ; the objects 
that are worth behaving like XML are very easy to handle : one can 
browse them with XPath and update them with something like XUpdate

One often say that :
-in Unix, everything is a file
-in OOP, everything is object
and now :
-in Active Tags, everything is XML
the last sentence should be "in XML-oriented programming, everything is 
XML", but it's not yet true ; I'm not sure that it will be true one day, 
but it is already true for Active Tags

-Active Tags :
http://disc.inria.fr/perso/philippe.poulard/xml/active-tags/
-an example of XPath over filesystems :
http://reflex.gforge.inria.fr/tutorial.html#N800FB4

-- 
Cordialement,

               ///
              (. .)
  --------ooO--(_)--Ooo--------
|      Philippe Poulard       |
  -----------------------------
  http://reflex.gforge.inria.fr/
        Have the RefleX !

• Follow-Ups:
  • RE: XML aggregation question?
    • From: Michael Kay
  • Re: XML aggregation question?
    • From: Florent Georges

• References:
  • RE: XML aggregation question?
    • From: Michael Kay